Gold pigments are gold-colored pigments and are used for aesthetic effects in various fields. For example, it has been used in industrial applications such as wallpaper, laminate, plastic molding, leather coating, silk printing, offset printing, painting of household appliances, and ceramic applications. For cosmetics, it is also used in various color cosmetics such as lipstick, nail polish, hair gel, eye shadow, and lip gloss. In addition, gold pigments are used in automotive interior and exterior paintings, construction and ship paints where high weatherability is required.
Korean Laid-open Patent Publication No. 1997-0001474 (Publication Date: Jan. 24, 1997) (hereinafter referred to as Patent Document 1) discloses a gold pigment.
Patent Document 1 discloses a gold pigment which can be used in paints, varnishes, powder coatings, printing inks, plastics and cosmetic formulations, wherein titanium dioxide (TiO2) and iron oxide (Fe2O3) are sequentially coated on a substrate.
However, only limited gold color can be obtained with white titanium dioxide and red iron oxide alone, and therefore it is difficult to properly realize gold color which has lesser red tones required by consumers.
Further, Korean Laid-open Patent Publication No. 2002-0070428 (Publication Date: Sep. 9, 2002) (hereinafter referred to as Patent Document 2) discloses a gold pigment.
FIG. 1 shows a conventional gold pigment, and schematically shows a gold pigment that can be derived from Patent Document 2.
Referring to FIG. 1, the illustrated gold pigment includes, on a substrate 100, a first layer 110 formed by mixing TiO2 and Fe2O3, a second layer 120 formed of SiO2, a third layer 130 formed of TiO2, and a fourth layer 140 formed of Fe2O3 or a mixture of Fe2O3 and TiO2.
FIG. 2 schematically shows another conventional gold pigment.
Referring to FIG. 2, the illustrated gold pigment includes, on a substrate 100, a first layer 210 formed of TiO2, a second layer 220 formed of SiO2, a third layer 230 formed of TiO2, and a fourth layer 240 formed of Fe2O3, similarly to the gold pigment shown in FIG. 1.
In the case of the gold pigment shown in FIGS. 1 and 2, there is a limitation that gold color is obtained by a combination of white titanium dioxide and red iron oxide in general, except that a coating layer formed of colorless SiO2 is formed in an intermediate layer.